TEHRAN, Iran (CNN) -- He's a key Iranian politician whose name is on the lips of opponents, supporters and experts alike in the bloody aftermath of the Iran's presidential elections.

But despite the chaos that's plagued the Islamic Republic for the past two weeks -- even resulting in the brief detention of his daughter -- former President Ali Akbar Hashemi Rafsanjani has remained silent and largely unseen.

The last time the world saw Iran's assembled leadership was June 19, when Iran's supreme leader, Ayatollah Ali Khamenei endorsed the victory of hard-line incumbent President Mahmoud Ahmadinejad in the hotly contested June 12 election at Friday prayers. But Rafsanjani was missing among the group of Islamic power brokers.

"Ayatollah Rafsanjani is the second-most powerful man in Iran -- up until now certainly -- has always been in opposition to Ahmadinejad," Hooman Majd, an Iranian-American author, told CNN Saturday. "He opposed him in the presidential race in 2005 and has been relatively opposed to him publicly and very opposed to him privately in his policies."

Whether the leadership will regroup to resolve the situation internally rather than air out the laundry publicly "is an open question," Majd said.

Rafsanjani, who supported Mir Hossein Moussavi -- a reformist and chief rival to hard-line incumbent President Mahmoud Ahmadinejad -- is chairman of the Assembly of Experts, which is responsible for appointing or removing the supreme leader.

There were widespread rumors that Rafsanjani has been in the Iranian city of Qom trying to rally a coalition of clerics and political figures against Khamenei, who fully supports Ahmadinejad.

During televised debates leading up to the election, Ahmadinejad publicly accused Rafsanjani of corruption as the unprecedented drama over the presidential race continued to grip voters.

For his part, Rafsanjani said Ahmadinejad's "baseless and irresponsible" statements brought back "bitter memories" of anti-revolutionary groups in the aftermath of Iran's 1979 Islamic revolution.

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Rafsanjani, 75, is one of Iran's richest citizens. He was a political activist in the 1960s and 1970s, and was imprisoned several times under the U.S.-backed Shah. Rafsanjani became a close confidant of Ayatollah Ruhollah Khomeini, who led the Islamic revolution which eventually overthrew the Shah's regime in 1979.

After the revolution, Rafsanjani held the powerful role of speaker of Iran's parliament in the 1980s, then went on to serve two terms as president from 1989 until 1997. He ran for president again in 2005 but lost in a second round of voting to Ahmadinejad.

In 2006, Argentina's chief prosecutor charged the former president and his aides with ordering the 1994 bombing of a Jewish cultural center in Buenos Aires. The attack killed 85 people and wounded about 300.

In his current position, Rafsanjani is the "one man who can have reconciliation between the opposition and Ayatollah Khamenei," Abbas Milani, the director of Iranian Studies at Stanford University, told CNN in a recent interview. Read more about Iran's power structure

"He occupies two very important institutions in the Islamic Republic, one designed to resolve constitutional conflict, and more importantly the [Assembly] of Experts for leadership, which can in fact remove Ayatollah Khamenei and have a new replacement for him," Milani said.

Still, even as the government crackdown on protesters turned violent and his own daughter, Faezeh, and four others were briefly detained for taking part in a rally, Rafsanjani has not come forward, leaving observers and opponents to wonder about his next move.